README.md

Storeon undo

Tiny module for Storeon which is adding undo functionality to your state. This means that now you can undoing or redoing the events in the state.

It is just 377 bytes module (it uses Size Limit to control the size) without any dependencies.

import { undoable, UNDO, REDO } from "@storeon/undo/full";

const store = createStore([
  /* all your modules */
  undoable,
]);

// now you can use UNDO and REDO with dispatch
dispatch(UNDO);

Installation

npm install @storeon/undo
# or
yarn add @storeon/undo

If you need to support IE, you need to compile node_modules with Babel.

Usage

You can use this module in two ways:

• store history for all state
• store history only for specific keys

Store history for all state

To using the undo/redo functionality you just need to add the undoable module to createStore.

import { createStoreon } from "storeon";
import { undoable, UNDO, REDO } from "@storeon/undo/full";

let counter = (store) => {
  store.on("@init", () => ({ counter: 0 }));

  store.on("inc", (state) => ({ counter: state.counter + 1 }));
  store.on("dec", (state) => ({ counter: state.counter - 1 }));
};

const store = createStoreon([counter, undoable]);

And now you can use the functions undo and redo to manipulate the history.

const Counter = () => {
  const { dispatch, counter } = useStoreon("counter");
  return (
    <React.Fragment>
      <div>{counter}</div>
      <button onClick={() => dispatch("inc")}>Inc</button>
      <button onClick={() => dispatch("dec")}>Dec</button>
    </React.Fragment>
  );
};

const UndoRedo = () => {
  const { dispatch } = useStoreon();

  return (
    <>
      <button onClick={() => dispatch(UNDO)}>Undo</button>
      <button onClick={() => dispatch(REDO)}>Redo</button>
    </>
  );
};

Store history only for specific keys

If you need history only for some particular keys in state you can use createHistory function:

import { createHistory } from "@storeon/undo";

// history will be collect only for key `a`
const history = createHistory(["a"]);
const { UNDO, REDO } = history;

createStore([
  /* all your modules */
  history.module,
]);

// to change the history use the UNDO and REDO from `history` object
dispatch(UNDO);

API

createHistory(paths, config)

paths parameter

type paths = Array<String>;

The keys of state object that will be stored in history

config parameter

type config.key = String

The default state key for storing history, when omitted:

• if paths is not empty will be generated based on paths content
• otherwise will default to 'undoable'

LICENSE

MIT

Acknowledgments

This module based on Implementing Undo History recipe article.